I have very finely tuned intuitive responses and my intuition usually serves me well, in that I make a fair few decisions based on what my gut instinct is telling me without any real hard evidence, and later my decisions are substantiated by the outcomes.

But sometimes it would appear that some people believe their intuition is telling them something when the reality is much, much different. Like for example, the jealous spouse who imagines his partner is cheating with no evidence whatsoever to back it up and the partner isn't cheating?

I think you did a great job answering your own question. Intuition is a gut feeling you get, matched with a good probability of outcomes. Paranoia is when the person has very unrealistic thoughts with no possiblity of coming true.